1. Field of the Invention
The present invention relates generally to the safe refilling of battery cells to a predetermined level. More particularly, the present invention pertains to a new and improved battery electrolyte cell plug which automatically controls the liquid level in the battery cell.
2. Description of the Prior Art
There is an inherent danger in refilling the electrolyte levels of wet cell batteries. For instance, the batteries of an electric golf cart need to be recharged after a designated period of use. Most course maintenance programs charge the batteries every day if the golf cart was used for 18 holes. This constant charging and discharging will result in loss of electrolyte due to evaporation. If the level of electrolyte in a given battery cell drops below the tops of the electrode plates, irreparable damage to the plates can occur. Also there is an increased corrosion of active material which leads to the detriment of cell life and quite often there is an increased risk of arcing between exposed, and possibly faulty plates, which could ignite any inflamable gases present. High temperatures in the cells will also cause expansion of the electrolyte. It is thereby important, to not only allow for expansion of the electrolyte in the cells by venting and dispensing of explosive gas mixtures, but also to periodically add electrolyte to the cells to compensate for the inherent losses.
Care must be also be exercised in order not to overfill the cells. If the intended liquid level is exceeded, this represents a reduction of the gasing space in the battery interior above the liquid level. This space is required for the collection of the gas/electrolyte mixture that forms during the operation and especially the charging of the battery. An overfilled cell may prevent oxygen and hydrogen, which are generated within the battery, from safely escaping into the atmosphere. A build up of these gases may buckle the plates and possibly lead to an explosive condition.
Maintenance personnel at golf courses are often relatively inexperienced. It is common for golf courses to hire teenagers for a summer job. Safety therefore is of paramount importance. The first step in refilling a battery is to remove the plugs, which in the case of a golf cart having six batteries would total 18 cell plugs. While refilling there is the danger of accidental splashing of sulfuric acid electrolyte on clothes, skin or eyes. The present invention seeks to provide a system whereby the danger to personnel is minimized, if not entirely eliminated, and the refilling operation reduced to a fraction of the time presently necessary. A very important factor when some golf courses have upwards of 60 to 80 golf carts.
U.S. Pat. No. 3,434,887 issued to A. E. Seckinger on Mar. 25, 1969, teaches the use of an apparatus to refill golf cart batteries. Seckinger shows the use of an automatic refill system that utilizes a pump to generate water flow. This system requires outside power to refill the cells.
U.S. Pat. No. 5,284,176 issued to Daniel Campau on Feb. 8, 1994, discloses a system for refilling a series of interconnected battery cells to a predetermined level by using individual refill valves, each associated with a single cell. A single supply reservoir is taught. Campau directs his teachings more to the composition of the supply tubing.
U.S. Pat. No. 4,749,633 issued to Leonard W. Elias on Jun. 7, 1988, shows a device that is mounted in the battery cell opening which receives the water. He utilizes a float that causes a valve pin to rise or fall in response to the liquid level in the cell.
U.S. Pat. No. 5,002,100 issued to Patrick Frederick on Mar. 26, 1991, discloses a gravity feed water reservoir which feeds water to a plurality of cell openings. Frederick discloses a valve member extending into each cell but not as a cell cap.
U.S. Pat. No. 4,522,896 issued to Barry S. Iseard on Jun. 11, 1985, teaches of an automatic watering system and the use of cell caps, adapted for retrofitting an existing battery.
U.S. Pat. No. 4,007,764 issued to Royal F. Bandemor on Feb. 15, 1977 is an automatic fluid filling device wherein the device itself consists of a plurality of members, each removably insertable into a battery cell. The cells are connected in series with the reservoir at one end of the series. This system requires a pump for recirculation.
U.S. Pat. No. 4,386,141 issued to Evert C. Weidner et al. on May 31, 1983, teaches a battery watering refill device for maintaining a predetermined electolyte level in each cell of a battery.
U.S. Pat. No. 4,219,612 issued to Edwin Tatlock on Aug. 26, 1980, teaches the use of a vent plug to allow the potential explosive mixture of gases to vent through the safety of a flame trap.
U.S. Pat. No. 4,113,925 issued to Werner Kohler et al. on Sep. 12, 1978, teaches the need to address the dangers of over filling an electrolyte cell and hazardous gas/electrolyte mixture that forms during the charging of the battery.
The concepts of the present invention are suggested for a host of possible applicatons. Electrically powered golf carts are discussed, but many other possible applications are readily seen. One large application area would be in material handling equipment where the handling unit comprises the use of multiple packs of batteries. Therefore, it will be appreciated that the invention can be utilized by any equipment that is battery powered and the batteries are intended to be periodically recharged.
None of the above inventions, taken either singularly or in combination, are seen to describe the instant invention as claimed.